use JSON::MaybeXS to provide the JSON backend everywhere
Merge pull request #1341 from karenetheridge/topic/json_maybexs

consolidate JSON handling around JSON::MaybeXS, to provide a sane backend everywhere
don't include unknown authors in contributors
tidy contributors code
better title for faq page
use fontawesome instead of glyphicons in more places
improve display of heading anchors
remove unused leaderboard css
remove unused not_found styles
remove unused and redundant styles
move css code to less files
move styles from style.less to global.less or more specific files
whitespace cleanup in less
use nested less rules rather than repeating selectors
apply main layout with content class rather than separately for various classes
set fonts using bootstrap variables
include syntax highlighter via less to make it easier to extend

allows aopying the syntax highlighter styles onto our own selectors
without needing to modify the syntax highlighter files directly.
move more syntax highlighter styles
link packages in syntax highlighter via monkey patch rather than source mod
update syntax highlighter to 3.0.9